Internal combustion engine and a method for controlling such an internal combustion engine

Abstract

The disclosure relates to a method for operating an internal combustion engine in a six-stroke mode, wherein the engine comprises at least one cylinder with a reciprocating piston, each cylinder having at least one inlet and outlet valve. The method involves performing a first stroke where a gas comprising at least air is induced into a combustion chamber from an intake conduit; a second stroke where the gas and injected fuel is compressed; a third stroke where the compressed fuel/gas mixture is expanded following an ignition; a fourth stroke where combusted exhaust gas is expelled through a catalyst body into a first exhaust conduit; a fifth stroke where pressurized fuel and pressurized heated water is injected into the combustion chamber to be expanded; and a sixth stroke where steam and gaseous fuel mixture is expelled through the catalyst body into a second exhaust conduit.

What is claimed is: 
     
       1. A method for operating an internal combustion engine in a six-stroke mode, wherein the engine includes a cylinder having a reciprocating piston, an inlet valve and an outlet valve, the method comprising the following steps performed in sequence;
 a first stroke where a gas including at least air is induced into a combustion chamber of the cylinder from an intake conduit; 
 a second stroke where the gas and injected fuel are compressed; 
 a third stroke where the compressed fuel/gas mixture is expanded following an ignition; 
 a fourth stroke where combusted exhaust gas is expelled through a catalyst body into a first exhaust conduit; 
 a fifth stroke where pressurized fuel and pressurized heated water are injected directly into the combustion chamber to be expanded; and 
 a sixth stroke where steam and gaseous fuel mixture is expelled through the catalyst body to be reformed and subsequently directed into a second exhaust conduit. 
 
     
     
       2. The method according to  claim 1  further comprising heating the catalyst body using the exhaust gas expelled during the fourth stroke. 
     
     
       3. The method according to  claim 1  wherein a heat exchanger is heated in the first exhaust conduit using the exhaust gas expelled during the fourth stroke. 
     
     
       4. The method according to  claim 1  wherein the supplied water is pre-heated using the exhaust gas expelled during the fourth stroke. 
     
     
       5. The method according to  claim 1  wherein the fuel supplied during the fifth stroke is pre-heated using the exhaust gas expelled during the fourth stroke. 
     
     
       6. The method according to  claim 1  further comprising heating the expelled steam and gaseous fuel mixture using the catalyst body and reforming the fuel into hydrogen and oxides of carbon. 
     
     
       7. The method according to  claim 6  wherein the reformed fuel is collected for subsequent mixing with induced intake air. 
     
     
       8. The method according to  claim 1  wherein the expelled steam in the second exhaust conduit is condensed. 
     
     
       9. The method according to  claim 1  further comprising controlling the flow of expelled gas between the first and the second exhaust conduits using a controllable valve. 
     
     
       10. An internal combustion engine operable in a six-stroke mode, the engine comprising:
 a cylinder having a reciprocating piston and an inlet valve and an outlet valve; 
 an intake conduit connected to the cylinder; 
 a flow controlling valve; and 
 an exhaust conduit connected to the cylinder, the exhaust conduit including a catalyst body arranged downstream of the outlet valve and upstream of the flow controlling valve; 
 wherein the six-stroke mode comprises a first stroke where a gas including at least air is inducible into a combustion chamber of the cylinder from the intake conduit, a second stroke where the gas and injected fuel are compressible, a third stroke where the compressed fuel/gas mixture is expandable following an ignition, a fourth stroke where combusted exhaust gas is expellable, a fifth stroke where pressurized fuel and heated water are injectable directly into the combustion chamber to be expanded, and a sixth stroke where the steam and gaseous fuel mixture is expellable through the catalyst body to be reformed, and wherein the flow controlling valve is arranged to direct exhaust gas into a first exhaust conduit connected to the exhaust conduit during the fourth stroke and to direct expelled steam and a reformed fuel from the catalyst body into a second exhaust conduit connected to the exhaust conduit during the sixth stroke. 
 
     
     
       11. The internal combustion engine according to  claim 10  wherein the first exhaust conduit comprises an exhaust heat exchanger arranged to heat the water prior to injection during the fifth stroke. 
     
     
       12. The internal combustion engine according to  claim 10  wherein the first exhaust conduit comprises an exhaust heat exchanger arranged to heat the fuel prior to injection during the fifth stroke. 
     
     
       13. The internal combustion engine according to  claim 10  wherein the second exhaust conduit comprises a condenser arranged to remove steam and a reservoir arranged to collect reformed fuel prior to induction into the combustion chamber. 
     
     
       14. A non-transitory storage medium comprising computer executable instructions for use in an apparatus for controlling an internal combustion engine that includes at least one cylinder with a reciprocating piston, each cylinder having an inlet valve and an outlet valve, wherein when the instructions are executed the apparatus is operable to control operation of the engine in a six-stroke mode including:
 a first stroke where a gas including at least air is induced into a combustion chamber from an intake conduit; 
 a second stroke where the gas and injected fuel are compressed; 
 a third stroke where the compressed fuel/gas mixture is expanded following an ignition; 
 a fourth stroke where combusted exhaust gas is expelled through a catalyst body into a first exhaust conduit; 
 a fifth stroke where pressurized fuel and pressurized heated water are injected directly into the combustion chamber to be expanded; and 
 a sixth stroke where steam and gaseous fuel mixture is expelled through the catalyst body to be reformed and subsequently directed into a second exhaust conduit. 
 
     
     
       15. The method according to  claim 1  further comprising controlling flow into the first and second exhaust conduits using a controllable valve that is spaced away from the combustion chamber. 
     
     
       16. The method according to  claim 15  wherein the fourth stroke involves expelling the combusted exhaust gas through the outlet valve, which is located adjacent the combustion chamber, and into an exhaust conduit, and wherein the controllable valve is arranged in a first position to cause the combusted exhaust gas to flow from the exhaust conduit into the first exhaust conduit. 
     
     
       17. The method according to  claim 16  wherein the sixth stroke involves expelling the steam and gaseous fuel mixture through the outlet valve and into the exhaust conduit, and wherein the controllable valve is arranged in a second position to cause the mixture to flow from the exhaust conduit into the second exhaust conduit. 
     
     
       18. The method according to  claim 1  wherein the outlet valve is open during the fourth and sixth strokes, and closed during the fifth stroke.